Withdrawal Study Details Effects of Levoketoconazole in Cushing's Syndrome

Maria Fleseriu, MD

New research presented at the American Academy of Clinical Endocrinology (AACE) annual meeting provides insight into the effects of treatment with levoketoconazole among patients with endogenous Cushing’s syndrome.

An analysis of data from a double-blind, placebo-controlled, randomized withdrawal study, results of the study demonstrate levoketoconazole provided benefits across a range of etiologies and provide evidence of levoketoconazole-specific effects through the withdrawal and reintroduction of therapy during the trial.

“This LOGICS study showed that treatment with levoketoconazole benefitted patients with Cushing’s syndrome of different etiologies and a wide range in UFC elevations at baseline by frequent normalization of mUFC and concurrent improvements in serum cholesterol,” said Maria Fleseriu, MD, professor of medicine and neurological surgery and director of the Northwest Pituitary Center at Oregon Health and Science University, during her presentation. “The benefits observed were established as levoketoconazole-specific via the loss of therapeutic effect upon withdrawal to placebo and restoration upon reintroduction of levoketoconazole.”

An orally administered cortisol synthesis inhibitor approved by the US FDA for treatment of endogenous hypercortisolemia in adult patients with Cushing’s syndrome considered ineligible for surgery, levoketoconazole received approval based on results of the phase 3 open-label SONICS trial, which demonstrated . Launched on the heels of SONICS, the current trial, LOGICS, was designed as phase 3, double-blind, placebo-controlled, randomized withdrawal study aimed at assessing the drug-specificity of cortisol normalization in adult patients with Cushing’s syndrome through a comparison of the effects of withdrawing levoketoconazole to placebo against continuing treatment.

The trial began with an open-label titration maintenance phase followed by a double-blind randomized withdrawal phase and a subsequent restoration phase, with the randomized withdrawal and restoration phase both lasting 8 weeks. A total of 89 patients with Cushing’s syndrome received levoketoconazole to normalize mUFC. Of these, 39 patients on a stable dose for 4 weeks or more were included in the randomized withdrawal stage of the study. These 39, along with 5 completers of the SONICS trial, were randomized in a 1:1 ratio to continue therapy with levoketoconazole or placebo therapy, with 22 patients randomized to each arm.

The primary outcome of interest in the study was the proportion of patients with loss of mean urinary free cortisol response during the randomized withdrawal phase of the study, which was defined as an mUFC 1.5 times the upper limit of normal or greater or an mUFC 40% or more above baseline. Secondary outcomes of interest included mUFC normalization at the end of the randomized withdrawal phase of the study and changes in comorbidity biomarkers.

Overall, 21 of the 22 patients randomized to placebo during the withdrawal stage met the primary endpoint of loss of mUFC compared to just 9 of 22 among the levoketoconazole arm of the trial (treatment difference: -54.5% [95% CI, -75.7 to -27.4]; P=.0002). Additionally, at the conclusion of the randomization phase, mUFC normalization was observed among 11 patients in the levoketoconazole arm of the trial compared to 1 patient receiving placebo (treatment difference: 45.5% [95% CI, 19.2 to 67.9]; P=.0015).

Further analysis indicated the restoration of levoketoconazole therapy was associated with a. Reversal of loss of contrail control in most patients who had been randomized to placebo. Investigators pointed out the mean change from randomized withdrawal baseline to the end of the randomized withdrawal period in total cholesterol was -0.04 mmol/L for levoketoconazole and 0.9 mmol/L for placebo (P=.0004) and the mean change in LDL-C was -0.006 mmol/L and 0.6 mmol/L, respectively (P=0.0056), with the mean increases in cholesterol observed among the placebo arm reversed during the restoration phase.

In safety analyses, results suggest the most commonly reported adverse events seen with levoketoconazole treatment, during all study phases combined were nausea and hypokalemia, which occurred among 29% and 26% of patients, respectively. Investigators also pointed out liver-related events, QT interval prolongation, and adrenal insufficiency, which were respecified adverse events of special interest occurred among 10.7%, 10.7%, and 9.5% of patients receiving levoketoconazole, respectively.

This study, “Levoketoconazole in the Treatment of Endogenous Cushing’s Syndrome: A Double-Blind, Placebo-Controlled, Randomized Withdrawal Study,” was presented at AACE 2022.